The physiological effect of an electric shock depends chiefly on the magnitude of current that passes through the body, following the perception-to-fatal scale used in electrical safety.

The scenario describes a mild shock where the technician stays fully conscious, which tells us the current was small, only a few milliamperes at the level of perception and let-go.

At such low currents the effect is stimulation of sensory nerves and muscles, felt as a sharp tingling sensation together with involuntary muscle contraction as the muscles twitch.

Immediate cardiac arrest requires currents large enough to disrupt the heart's rhythm (ventricular fibrillation), which would not leave the person conscious, so that option is far too severe.

Respiratory paralysis with a prolonged coma likewise needs a much heavier current sustained across the chest, again inconsistent with a mild, survivable shock.

Widespread internal tissue destruction and severe skin burns are heat effects of very high fault currents, typical of high-voltage contact, not of a mild tingle.

Hence, the answer is Involuntary muscle contraction and a sharp tingling sensation.